We recently adopted a 3 year old Pekingese from a local shelter. In the shelter, the dog appeared very clam and loving but once we got home the dog has had horrible behaviors. The dog does not allow either me or my husband to get anywhere in its personal space. If we reach to pet the dog, he growls and snaps. He is always very possessive of his food and snacks we give him, if we even walk in the area of his bowl he gets very upset and goes to attack.
My husband and I are both feeling frustrated and hopeless. We want to help this dog and create a loving, happy environment but don't know what to do. We try to be patient and not give up but I don't want anyone to get hurt. The last thing I want is return the dog to the shelter, but we are at a total loss for what to do to help this dog.
We would appreciate any advice out there!

"resource hoarding", as they call it, would be a pretty typical behaviour for a little guy that came from a shelter. They tend to be very vigilant about their food, toys, sleep area, and any other territory that they claim.

With respect to the food, I had the same problem with Buddy, although not as severe. The technique I used worked very fast, and before I knew it, Buddy was great with his food.

The first thing you want to do is teach the little guy to make a pleasant association between you and his food. It's important for the dog to know that "the floor" doesn't feed him; you do. In other words, don't have his food waiting for him in his dish; he needs to know that the food comes from you.

Start by sitting with him beside his food dish, and taking his kibble in the palm of your hand at his dinner time, giving him a little bit to start. Put the open palm of your hand with the kibble in his dish while you do this. Leave your hand relaxed, and you can praise him if you want. When he finishes that portion, give him the next portion. Slip in a little cheese this time. Do this for a couple of meals. For the next meal time, put his kibble in his bowl (be sure he sees you) and when he starts to eat it, slip in some cheese a few times during his meal. He'll actually stop eating and let you put your hand in the bowl, happily awaiting his treat!

Regarding the petting, are you bending over his head? Buddy also had this problem. It took him awhile to accept me leaning over him and he reacted to it. That's a fear/dominance problem. You may want to pet him by first squatting beside him, and petting him that way--no leaning over his head. Again, work up to that by training with treats (once you get the food thing remedied).

Resource guarding is pretty serious and if left unchecked can pose serious problems. Start by being a good leader. Make sure you make the dog work for everything from food to affection. I would start by hand feeding, but make sure you get the dog to perform some sort of command before each handful. Make them sit before going out, make them sit and be quiet before getting the leash on, make sure they are calm and sitting for affection. Do not let this dog up on the couch or bed for now. They need to earn this privilege and he hasn't yet. He sees these things as a "resource" and is guarding them. For treats make sure you present them in a closed fist and let the dog sniff. He may not take it until his mouth is soft and he can take it from the middle of your hand. He will begin to associate all the good things that happen to him come from you. Do not yell at or smack this dog (not that I think you would). Doing so will only reinforce his fear and make him worse. It will get a bit worse before it gets better. His behaviors are rewarding to him and he will try to hold on to them out of fear (agression in most cases is fear based). About 2 weeks in to training him you will reach his extinction burst where things seem to get worse. If you can get through that you will see a marked improvement. Make sure everyone in the house is extremely consistant and knows the rules. No one "sneaks" him on the couch (like my EX husband lol) or free feeds him. If you need anything clarified or have any other questions please ask. There are loads of qualified trainers and behaviorists on this board and are always willing to share. Thank you so much for rescuing.

I am currently dealing with a foster dog at this time with some serious aggression issues as well. It is unprovoked, no triggers and therefore no way to address at this time. He has displayed some very troubling behaviour which through my journal enteries, I cannot detect how, or why. For me, it's not a question of guarding or territoral issues. He can go from being the most loving, affectionate sweet dog into a raving vicious animal within seconds. He then recovers and is remorseful...very disturbing.

What I have done now is I brought the dog to our vet for a full vet check with blood work up. Hopefully, (or not hopefully) I will find out if there is something medically wrong.

Ask you vet to do a full blood work on organs such as liver, kidneys. Check for a possible seizure disorder and hypothyroidism. Also ensure that there are no worms such as hook worms, giardia or coccidia. Infact, have the fecal completely analyzed.

Just so that you know, I have had now 79 foster dogs. All my own animals have been adopted through a rescue or shelter. This is the first time in all these years that I have been faced with a very extreme case. This situation that I am in with this particular dog, is not a norm.

Whatever you do however, it is best to consult with those where you got the dog from. They may provide some great tips and/or a more of a background check on if this has ever happened before.

This is not saying that you and I are living the same scenario, but perhaps the process of elimination starts with a full medical and blood work.